MYXOMYCETES 



6. Tubules of the capillitium filled with lime throughout. 7. 

 Tubules of the capillitium with deposits of lime at the knots, with in- 

 tervening vacant spaces. 8. 



Tubules of the capillitium without lime. II. 



7. Stipe prolonged into the sporangium as a columella. SCYPHIUM. 

 Stipe not entering the sporangium. BADHAMIA. 



8. Stipe prolonged as a columella. 9. 

 Stipe not entering the sporangium. IO. 



9. Sporangium oblong, with a re-entrant apex. PHYSARELLA. 

 Sporangium globose, with a convex apex. CYTIDIUM. 



10. Sporangia opening with an operculum. CRATERIUM. 

 Sporangia opening irregularly. PHYSARUM.* 



11. Wall of sporangium with the outer calcareous layer usually compacted 



into a smooth continuous crust. CHONDRiODERMA.f 



Wall of sporangium bearing minute stellate lime crystals. DiDYMlUM. 

 W T all of sporangium with an outer layer of large scales of lime. 



LEPIDODERMA. 



12. Aethallia formed of confluent sporangia with columellae, whitish ; 



lime on the surface in the form of stellate crystals. SPUMARIA. 



Aethallia compact, without columellae, yellowish or brownish ; lime 



on the walls in the form of rounded granules. FULIGO. 



13. Plasmodium forming simple sporangia. 14. 

 Plasmodium forming a large roundish aethallium. AMAUROCHAETE. 

 Plasmodium forming elongate irregular plasmodiocarps. 19. 



14. Capillitium suspended from the discoid enlargement of the top of the 



columella, nearly simple. ENERTHENEMA. 



Capillitium growing from a more or less elongate columella. 15. 



Columella wanting ; sporangia ovoid, polished. LEOCARPUS. 



15. Columella extending nearly to the apex of the sporangium. 18. 

 Columella scarcely extending to the center of the globose sporangia. 16. 



16. Stipe and columella filled with lime, whitish or yellowish. DiACHAEA. 

 Stipe and columella brownish or black. 17. 



17. Threads of capillitium several times forked, not forming a net- work. 



CLASTODERMA. 

 Threads of capillitium anastomosing to form a net- work. 



LAMPRODERMA. 



* Tilmadoche is separated from this genus by some. 



| Morgan adopts the generic name Didcnna for this, but it is untenable, 

 since it was originally founded by Persoon for a single species, not now 

 regarded as belonging to this genus. 



